KINETICS AND KINETIC ISOTOPE EFFECT IN PENTAVALENT PLUTONIUM DISPROPORTIONATION ACTIVATED BY POWER ULTRASOUND

A kinetic isotope effect in Pu(V) disproportionation has been observed in nitric acid solution under the effect of power ultrasound with int ensity 0.9 W . cm(-2) and frequency 22 kHz. The isotope separation coe fficient alpha for Pu-242/Pu-239 isotopes was found to be 1.0081 at 20 degrees C. Without sonication the k.i.e. was not observed. The rate c onstant of Pu(V) disproportionation was found to be accelerated under sonication, The rate constant determined was (5.7 +/- 0.6). 10(-3) l(2 ) . mol(-2). s(-1) at l = 0.9 W . cm(-2) upsilon = 22 kHz, [HNO3] = 0. 5 mol . l(-1) and T = 20 degrees C. It is supposed that the accelerati on of Pu(V) disproportionation and the kinetic isotope effect are due to the activation of plutonoyl groups in the interface between the cav itation bubble and the bulk solvent.